Patent GB-633824-A (GB)
Title: Improvements in and relating to the preparation of beta-substituted polymethine dyestuffs
IPC: C09B23/12
Filed: 1945-12-06
Abstract: 2-(2 - Methylmercapto - 3 - p - dimethylaminobenzalpropenyl)-benzthiazole ethiodide is prepared by boiling together 2-(2-methylmercaptopropenyl)-benzthiazole ethyl methosulphate, p-dimethylaminobenzaldehyde and acetic anhydride, and treating the product with aqueous potassium iodide solution.  1 - Phenyl - 3 - methyl - 4 - (31 - ethyldihydrobenzthiazolylidene - g  - methylmercaptobutenylidene)-5-pyrazolone is prepared by reacting together 2 - (2 - methylmercaptopropenyl) - benzthiazole ethyl methosulphate, 4-anilidomethylene - 1 - phenyl - 3 - methyl - 5 - pyrazolone, acetic anhydride, and sodium acetate.  2 - (2 - Phenylmercaptopropenyl) - benzthiazole ethochloride is prepared by reacting 2-(2-chloropropenyl) - benzthiazole ethochloride with sodium thiophenolate.  2 - (2 - Methoxypropenyl) - benzthiazole ethiodide is prepared by reacting 2-acetylmethylene-N-ethylbenzthiazoline with methyl iodide.  Samples have been furnished under Sect. 2 (5) of five dyes, the preparation of the intermediates for which is as follows. 2-(b -ethoxy: b  - methylvinyl) - benzoelenazole methyl ethyl sulphate is prepared by refluxing 2-acetylmethylene - N - methyldihydrobenzselenazole with diethyl sulphate and benzene, 2-(b -ethoxy: b -methylvinyl)-6-methylbenzthiazole methyl ethyl sulphate, 2-(b -ethoxy: b -methylvinyl)-benzthiazole benzyl ethylsulphate, and 2-(b -methoxy: b -methylvinyl) - 3 : 4 - (a  - methyltrimethylene) - benzthiazole dimethylsulphate are similarly prepared.  N - Acetyl - 2 - methyl - 1 : 2 : 3 : 4 - tetrahydroquinoline is prepared by boiling 2-methyl-1 : 2 : 3 : 4-tetrahydroquinoline with acetic acid and acetic anhydride. N-Thioacetyl-2-methyl-1 : 2 : 3 : 4-tetrahydroquinoline is prepared by refluxing the N-acetyl compound with P2S5 in toluene.  2 - Methyl - 3 : 4 - a  - methyltrimethylenebenzthiazole bromide is prepared by reacting the N-thioacetyl compound with bromine in chloroform.  2 - Acetyl - methylene - 3 : 4 - a  - methyltrimethylenedihydrobenzthiazole is prepared by reacting 2-methyl-3 : 4-a -methyltrimethylenebenzthiazole bromide in pyridine with acetaldehyde.  2-(b -Chloro-b -methylvinyl)-benzthiazole ethochloride is prepared by reacting 2-acetylmethylene - N - ethyl - 2 : 3 - dihydrobenzthiazole in benzene with POCl3. 2-(b -Benzthiazolylmercapto: b  - methylvinyl) - benzthiazole ethochloride is prepared by adding the b -chloro compound to a warm solution of the potassium salt of 2-mercaptobenzthiazole in pyridine.  Specification 623,990 is referred to.ALSO:Symmetrical and unsymmetrical polymethine dyes are prepared by reacting a compound of the general formula <FORM:0633824/IV (c)/1> wherein R1 is S-alkyl, S-aryl, S-substituted alkyl, Se-alkyl, Se-substituted alkyl, O-alkyl, O-substituted alkyl, or S-Q, wherein Q represents a heterocyclic nucleus (e.g. benzthiazole), Y represents the atom grouping necessary to complete a heterocyclic 5-membered ring which may have a fused-on aromatic ring, R is alkyl, aralkyl, aryl, carboxyalkyl, or a substituted or unsubstituted trimethylene bridge between the N-atom and the peri-C-atom, and X is an acid residue, either with an aromatic aldehyde, or with a compound of one of the formul  <FORM:0633824/IV (c)/2> and <FORM:0633824/IV (c)/3> wherein R3 is a group reacting with the CH3 group, Z is the non-metallic atoms to complete a 5- or 6-membered heterocyclic ring (which may have a fused-on aromatic ring, n is O or a positive integer, and R4 and X are as R and X above. Compounds of the general formula specified are 2-(2-methylmercaptopropenyl) - benzthiazole ethyl methosulphate, 2 - (2 - methylmercaptopropenyl) - 4 : 5 - naphthathiazole ethyl methosulphate, 2-(2-methylmercaptopropenyl) - 3 : 4 - trimethylene benzthiazole methosulphate, 2 - benzylmercaptopropenyl) - benzthiazole ethobromide, 2 - (b -carboxyethylmercaptopropenyl) - benzthiazole ethochloride, 2 - (2 - methylselenamercaptopropenyl) - benzthiazole ethyl methosulphate, 2 - (2 - methoxypropenyl) - benzthiazole ethiodide, and 2-(2-phenylmercaptopropenyl)-benzthiazole ethochloride.  3 : 31 - Diethyl - 9 - methylmercaptothiacarbocyanine perchlorate is prepared by boiling together 2 - (2 - methylmercaptopropenyl)-benzthiazole ethyl methosulphate, 2-methyl-mercaptobenzthiazole ethyl p-toluenesulphonate, pyridine, and triethylamine, and treating the product with aqueous sodium perchlorate.  3 : 31 - diethyl - 9 - methylmercapto - 4 : 5-benzthiacarbocyanine perchlorate, 3 - ethyl-31 : 41 - trimethylene - 9 - methylmercaptothiacarbocyanine perchlorate, 3 : 31 - diethyl-9 - methylmercaptothiaquinocarbocyanine perchlorate, 3 : 31 - diethyl - 9 - benzylmercaptothiacarbocyanine perchlorate, 3 : 31 - diethyl-9 - b  - carboxyethylmercaptothiacarbocyanine perchlorate, 3 : 31 - diethyl - 9 - phenylmercaptothiacarbocyanine chloride, 3 : 31 - diethyl - 9-methylselenamercaptothiacarbocyanine iodide, 3 : 31 - diethyl - 9 - methoxythiacarbocyanine perchlorate, and 3 - ethyl - 31 - methyl - 51-methylmercapto - 9 - methoxythiathiadiazolocarbocyanine perchlorate are similarly prepared.  3 - Ethyl - 31 - methyl - 9 - methylmercaptothiadicarbocyanine iodide is prepared by reacting together 2-b -acetanilidovinyl-benzthiazole methyl methosulphate and 2-(2-methylmercaptopropenyl)-benzthiazole ethyl methosulphate in the presence of acetic anhydride and sodium acetate, and treating the product with aqueous potassium iodide solution.  Samples have been furnished under Sect. 2(5) of 3 : 31 - dimethyl - 9 - ethoxy - thiaselenacarbocyanine perchlorate, of 3 : 31 : 61-trimethyl - 5 - methylmercapto - 9 - ethoxythiadiazolo - (1 : 3 : 4) - thiacarbocyanineiodide, of 3 p  - methyl - 31 - benzyl - 9 - ethoxy oxathiacarbocyanine methylsulphate, of 3-ethyl - 31 : 41 - (a  - methyltrimethylene) - 9-methoxythiacarbocyanine perchlorate, and of 3 - methyl - 31 - ethyl - 9 - benzthiazolyl - (2)-mercaptothiacarbocyanine perchlorate.  Specification 623,990 is referred to.